A legal digital signature is comprised of a digital signature hash validated against an organization's authentication infrastructure. This type of signature provides the same legal standing as a handwritten signature if it adheres to the requirements of the specific regulation it was created under (e.g., eIDAS in the European Union, NIST-DSS in the USA or ZertES in Switzerland). Digital signatures are used in e-commerce and in regulatory filings to implement electronic signature in a cryptographically protected way. Standardization agencies like NIST or ETSI provide standards for their implementation (e.g., NIST-DSS, XAdES or PAdES). For example, U.S. Pat. No. 9,495,546 discloses an electronic signing method.
Various point-to-point secure communication protocols provide cryptographic endpoint authentication for applications that communicate within client-server based networks for preventing eavesdropping, tampering, and message forgery during communications. SSH is a set of standards and associated network protocols that allow for establishing a secure channel between a local and a remote computer. This protocol uses public-key cryptography to authenticate the remote computer.
U.S. Pat. No. 8,990,572 discloses conducting secure smart card transactions with mobile devices. Federal Information Processing Standard Publication (FIPS) 201 is a United States federal government standard that specifies Personal Identity Verification (PIV) requirements for Federal employees and contractors. A PIV card is a card used for identity authentication and information access control. A PIV card can be a smart card, chip card, or integrated circuit card (ICC) is any pocket-sized card with or without an embedded integrated circuit. A PIV card reader is an electronic device that reads information contained in PIV cards. FIG. 1 shows a PIV card.
It is also known to apply features of biometric data to a hash generator that relies on boundaries to generate a hash, which is used to generate biometric keys. For example, FIG. 2 shows basic operation block diagram of an Iris biometric crypto system that uses a biometric template itself or a hash of the biometric as the biometric keys. FIG. 3 shows block diagram of a quantization scheme that constructs intervals for each element of a biometric feature vector shown in FIG. 2, where the biometric keys are generated by mapping the features into the intervals.
US Publication #20150143511 discloses biometric access controls. U.S. Pat. No. 7,481,364 discloses biometric identification device with smart card capabilities. U.S. Pat. No. 9,589,260 discloses authenticating electronic money using a smart card that takes biometric signature from a user as an input and transmits a recognition completion information to a communication terminal when the biometric signature inputted by the user matches a stored biometric signature. U.S. Pat. No. 9,323,914 discloses a smart card with partially or fully virtualized components that maximizes confidentiality of stored information using digitized unique biometric identifiers.
Multi-factor authentication (MFA) is a method of computer access control in which a user is granted access only after successfully presenting several separate pieces of evidence to an authentication mechanism—typically at least two of the following categories: knowledge (something they know) and possession (something they have) or a biometric parameter (something they are). Two-factor authentication (also known as 2FA) is a method of confirming a user's claimed identity by utilizing a combination of two different components. A personal identification number (PIN) are examples of something a user knows and a PIV card is something the user has. By authenticating the PIN number and information read from the PIV card, documents can be digitally signed by the user.
Various ways of placing e-signatures on documents are known. Adode's PDF documents, for example, can be e-signed by placing signature images, e.g., handwritten signatures, within documents. Docusign (https://www.docusign.com/products/electronic-signature) uses a system and method for approvals of agreements based on e-signatures. The DocuSign system can embed electronic signing into existing website, portals, and applications.
Asymmetric cryptography uses a pair of mathematically related keys known as public and private keys, which obviate the need for prior knowledge of a shared secret key amongst communicating participants in symmetric key cryptography. Public key infrastructure (PKI) is a known system for securing information using asymmetric key cryptography. In such systems, a party at one computer station digitally signs messages using a randomly created private key and a party at another computer station verifies the signature using a distributed public key derived from the private key. The public keys of the communicating participants are distributed in corresponding certificates, also known as Public Key Certificates, issued by one or more trusted parties called Certificate Authorities (CAs). PKI enables communicating parties to be authenticated to each other and to use the public key information in certificates to encrypt and decrypt messages.
By digitally signing the certificate, a central authority (CA) attests that the public key belongs to the identity, i.e., the person, organization, server, or other entity noted in the Certificate. The CA is often a trusted third party that issues digital Certificates for use by communicating parties. The requirement of trust obligates the CA to somehow verify the identity credentials of communicating parties. It is assumed that if the parties trust the CA and can verify its signature, they can also verify that a public key does indeed belong to whomever is identified in the certificate.
Applications often provide access to resources based on credentials supplied by the user. Typically, such applications verify user identity and provide access to resources based on roles. Roles are often used in financial or business applications to enforce policy. For example, an application might impose limits on who can sign documents depending on whether the signer is a member of a specified role. Role Based Access Control (RBAC) is handled via an <RBACRoles> X.509 Extensions. X.509 specifies formats for public key certificates, certificate revocation lists, attribute certificates, and a certification path validation algorithm.
U.S. Pat. No. 8,775,809 discloses biometrics based signatures in which a verifier attains a first biometric template of an individual to be verified based on a finger print. The verifier then receives a digital signature and a second biometric template and verifies the digital signature by using either the first or the second biometric template as a public key. The attained (first) biometric template is compared with the received (second) biometric template associated with the signature and if a match occurs, the verifier can be confident that the digital signature and the associated (second) biometric template have not been manipulated by an attacker for impersonation purposes. The drawback of the system is that biometric templates are used as a public key, which are shared with other nodes thereby preventing privacy of biometric data.
US Publication #20020176583 discloses a public-key infrastructure based on credentials that rely on a fingerprint that is presented to an authority of the public-key infrastructure. After reading biometric data derived from a fingerprint of a user at a biometric input device, the biometric data is signed with the private-key issued by the authority. The PKI infrastructure sends a certification request containing the public-key and the signed biometric data. After verifying and registering received data by the authority, the biometric data is sorted in a database and a corresponding certificate is returned. The certificate is stored in a token. After registration of the token, the public-key infrastructure allows signing and encrypting messages with digital signatures, on which a third party can rely on. In case of fraud biometric data taken from an unauthorized user can be stored in a database and later legally used as evidence. Therefore, it is known to use PKI certified biometric data to sign messages.
US Publication #20040059924 discloses a biometric signature system that employs biometric private keys (BioPKI) and a digital signature. The BioPKI uses a combination of biometric technology to access private keys in order to create digital signatures based on biometric authentication and industry-standard PKI technologies. BioPKI utilizes public key cryptography technology to encrypt the biometric signature information for transmission to the BioPKI server.
U.S. Pat. No. 9,037,851 discloses a user authorization system for authorization management with a public PKI certificate issuing server that issues a PKI certificate including a subscriber's biometric signature. The system also includes a sensing means that recognizes biometric patterns with a smart card that stores the subscriber's biometric signature and a PKI certificate, e.g., X.509 certificate, that verifies the user. The smart card transmits a signal to the terminal if the user's biometric pattern matches with the subscriber's biometric signature and transmits authorization information derived from the PKI certificate. The draw pack of the foregoing prior art is that the biometric data itself is not used for generating the private and public keys, which makes it susceptible to fraud if the PKI infrastructure is somehow compromised.
U.S. Pat. No. 7,188,362 discloses a smart card used to digitally sign messages by authenticating biometric data provided by a user. The smart card has a random number generator and an encryption module. In an enrollment mode, the biometric data analyzer receives biometric data from a user and triggers a random number generator to create a public key and a private key. The private key is stored in a tamper-resistant component on the smart card. The public key is transmitted to an external device, such as a computer. During a signing mode via a card reader interface, the smart card digitally signs incoming messages after verifying the user's biometric data. The draw pack of this prior art is that the biometric data itself is used for randomly generating the private and public keys, which makes it susceptible to fraud if the generator infrastructure is somehow compromised.
Blockchain technology is known. A blockchain is a continuously growing list of records, called blocks, which are linked and secured using cryptography. By design, blockchains are inherently resistant to modification of the data. A blockchain can serve as distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way. FIG. 4 shows a flow diagram of blockchain for when a user sends money to another user. FIG. 5 shows how data blocks are chained together by hash functions based on a Merkle table that acts as a hash ledger. The advantage of blockchain infrastructure to centralized infrastructures like PKI that use central ledgers is that blockchain is harder to compromise because distributed hash ledgers are used.
With expansion of workflow based document exchange platforms, there exists a need to integrate and use existing platforms for user verification. More specifically, there is a need for a system and method that leverages existing PIV card platforms to allow verified users to sign documents regardless of format for exchange between counterparties using an existing PKI infrastructure. In another instance, there is a need for a system and method that uses biometric data and user communities to obviate the need for a central PKI authority.